A minor injury that occurs during the unlikely combination of circumstances in which one is naked or wearing loose pants, trousers, slacks, shorts, or undergarments on a particularly warm day.

In order for it to happen, one must start a forward pendulous swing while initiating a free fall onto a hard surface, as if to sit. If the timing is precise, the hanging scrotum and concomitant testicles will descend upon the surface at the very bottom of its swing, at maximum kinetic energy, causing an impact not dissimilar to a mentally disabled man attempting to swing on a vine that is just a fraction too long (a Tardzan).

It was really hot out, and I had just peeled my balls off my taint, and plopped down on the bench and pulled a major Nutsack Tardzan.